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In this tutorial we're going to discuss about the topic list comprehension.

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Comprehension is allow us to create sequences from other sequences.

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List comprehension are a tool for transforming one list are any AI terrible sequence into another list.

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And this is the basic syntax for the list comprehension expression for item in list and a list comprehension.

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Returns a list they contest of square brackets containing the expression which needs to be executed

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for every element along with the for loop to iterate or word each element using an example we will understand

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how this works.

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So in our first example we want to create a list list to which is an exact copy of List 1.

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So we will try and understand this expression here.

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Use of for loop in order to retrieve every element in list 1 and every element in list 1 is denoted

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by this variable here.

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That is the input variable the variable representing elements of the input sequence so X is for the

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element in list 1.

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D X here it represents an output expression producing elements of the output list so if you want to

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create an exact copy of List 1 This is the expression.

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So this means for every element in list 1 The Element X is generated in list 2.

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So we will see this in Jupiter known book so here I have defined list 1.

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Now I'm going to create lists 2 which is an exact copy of List 1 by using the list comprehension.

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So the expression would be for x in list 1.

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That means for every element in list 1 I want to generate an element x in list 2.

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So let's execute this expression and then display list 2.

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So here we have list 2 which is a copy of list 1 now considered another example we want to create a

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list to where the elements in list 2 are a square of the elements in list 1.

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So let's put the expression in square brackets.

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And let's begin with the variable representing the element in the input sequence or x in list 1.

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And we want the elements in list 2 to be squared.

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So x 2 the password or two.

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So this means default low retrieves every element in list 1 and then squares the element and add to

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list to execute this expression in Jupiter notebook.

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So the expression for list who should be X to the power of to let's put this in parentheses and then

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default statement for x in list 1 and then execute the statement and then display this to.

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So as you can see using one single line of code we have created list 2 from list 1.

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So we have considered two examples for list comprehension.

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Now let's discuss the third example.

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Read element in list two will be included only if they satisfy a certain condition.

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So list comprehension can utilize conditional statements.

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So let's say this the same expression that we used for squaring all the elements in list one we are

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going to use the same expression.

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So X to the power of two.

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For x in list 1 and I want to put a condition that only if the element is greater than zero in this

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one then only square the element.

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So this statement would be if X greater than zero.

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So this particular statement checks for the elements with it is greater than zero.

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Only if it is greater than zero it is squared and then included in the new list.

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So let's execute this expression in Jupiter notebook so here in the Jupiter notebook I'm going to write

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the list comprehension statement.

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So let's begin with for loop 4D x in list 1 the element in the new list should be squared.

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Condition is if X greater than 0.

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So let's execute this and then display list 2.

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So as you can see there are four elements in list 1 which are greater than 0 and they have the elements

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have been squared.

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And then the new list.

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List 2 has been created.

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So this is about list comprehension.

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In this tutorial we will discuss about list constructor a list constructor should create a new list

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based on the past sequence.

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The sequence doesn't need to be a list.

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It can be any kind of sequence and this is how did list constructor is denoted list open close parentheses.

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And this is the syntax for the list constructor so you can pass an either a bill as a parameter to the

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list constructor.

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So first I'm going to pass a list containing elements such as 1 2 and 3 and C D output.

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Indeed you better known.

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So here I have the list constructor and I'm going to pass this sequence one comma too comma 3 and then

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execute the same so here.

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I have the list creator.

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Us now parse a string which is another I travel to the list constructor see I'm going to pass these

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string Biden and then execute this as you can see the list constructor has retrieved each of the characters

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in the string and then added to the list.

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And if you do not pass any parameters to the list constructor and empty list is created.

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So this is about list constructor.